The invention concerns a device for projecting a linear optical marking onto at least a boundary of a room, such as a floor surface, comprising a light source that emits a light radiation—such as laser radiation—along an optical axis, as well as a cuboid lens connected in series with the light source, which is penetrated by the optical axis, both reflects and refracts the radiation, and features frontal and rear surfaces as transverse surfaces, which run at an angle to the optical axis. The invention also relates to a method for projecting a linear optical marking onto at least one boundary such as a floor surface of a room by fanning a light radiation, such as laser radiation, emitted from a light source and at least partly reflecting and refracting it at or in an optical lens, whereby radiation is reflected and refracted in such a way that the optical marking is projected both in front of and behind the light source.
DE-A-102 17 108 discloses a laser beam device for use in the construction industry. To generate a line running over a wide angle without interruption, the invention provides that a bundle of laser beams penetrating a collimator-lens strikes a rod lens that features a semitransparent surface on the side facing the light source for the purpose of reflecting a linear laser beam in the direction of the light source. The light that is not reflected then penetrates a fully transparent surface of the rod lens facing away from the light source and is refracted to produce a linear light beam in a second direction running in opposition to the first direction.
To solve the problem of projecting a line of visible light on a surface that begins immediately in front of a housing containing the light source, U.S. Pat. No. 6,502,319 provides multiple cylinder lenses and mirrors by means of which the light beam emitted from the light source is fanned to the extent required.
In light-beam leveling device disclosed in DE-U-203 04 117 and DE-U-203 04 114, line lenses, which are composed of sections of differing focal lengths, are arranged in front of a light source, by means of which a linear light beam should be produced.
To solve the problem of generating two lines intercepting at a right angle on a workpiece below an optical marking device, DE-C-199 53 114 proposes having two projection devices arranged laterally to one another, each of which comprises a light source and optics arranged in the optical path thereof.
To solve the problem of fanning out the light beam, U.S. Pat. No. 3,984,154 proposes a lens that features the shape of a hollow cylindrical body section, an edge face of which is struck by a collimated laser beam. To ensure the sufficient outward reflection of the light, the inner surface of the lens features a reflective layer.
To solve the problem of generating linear markings, JP-A-2004094123 uses a rod lens, where sections of the outer surface feature a reflective layer so that the light striking it is immediately reflected. In the areas in which this reflective layer is not provided, light is able to penetrate the lens.
A device of the type initially mentioned is known from U.S. Pat. No. 6,935,034. The lens used to fan out a laser beam is of cuboid geometry with a rounded edge facing away from the light source to facilitate the desired fanning of the light penetrating the lens.
To solve the problem of generating optical markings on an object, EP-A-1 054 286 proposes using two pivotably mounted reversing devices arranged in an optical path of a light bundle.
To solve the problem of forming and guiding a radiation field of one or more solid state lasers, DE-A-195 14 626 proposes using refractive elements, by means of which the striking radiation is reversed or refracted in one direction.
A lighting system, for example for motor vehicles or buildings, disclosed in EP-B-0 767 393 comprises a transparent plate with recesses and projections in the side surfaces, which run at an angle to the striking direction of the radiation of the lighting system. Owing to this design of the transparent plate, the reflected and refracted radiation exits the plate exclusively on the side facing away from the light source.
To solve the problem of generating crossing lines on, for example, a floor surface, DE-U-20 2004 007 476 proposes connecting channel-shaped lenses in series to light sources.